In an information recording medium, such as a CD and a DVD, for example, as described in patent documents 1 and 2 or the like, there is also developed an information recording medium, such as an optical disc of a multilayer type or dual layer type or multiple layer type, in which a plurality of recording layers are laminated or stacked on the same substrate. Then, on an information recording apparatus, such as a CD recorder, for performing the recording with respect to the dual layer type, i.e., two-layer type optical disc, laser light for recording is focused or condensed on a recording layer located on the front as viewed from the irradiation side of the laser light (hereinafter referred to as an “L0 layer”, as occasion demands), to thereby record information into the L0 layer in an irreversible change recording method by heat or in a rewritable method. Moreover, the laser light is focused or condensed on a recording layer located on the rear of the L0 layer as viewed from the irradiation side of the laser light (hereinafter referred to as an “L1 layer”, as occasion demands), through the L0 layer or the like, to thereby record information into the L1 layer in the irreversible change recording method by heat or the rewritable method.
On the other hand, there is also disclosed a technology of performing the recording or reproduction in an “opposite method” or the like with respect to the L0 layer and the L1 layer. The “opposite method” herein is a recording or reproduction method in which the directions of track paths are opposite between the two recording layers, for example.
In the link (linking) of such a write-once type optical disc, such as a DVD-R, three types of linking sizes are defined, which are 32 KB, 2 KB, and lossless linking. In the case where the linking size is 32 KB, if the recording is completed by a unit of 1ECC block, for example, information for the link is recorded within a second sync frame of a sector at the head of the ECC block, before a 32 KB linking loss area is provided. Then, padding is performed until the 32 KB linking loss area is filled up, and the additional or postscript recording of user data is started from a NWA (Next Writable Address). As described above, in the case where the linking size is 32 KB, overhead increases more, however, error correction by the unit of ECC block is not influenced by the link, resulting in high-quality.
On the other hand, in the case where the linking size is 2 KB in which padding is performed until a 2 KB linking loss area is filled up, there is such a characteristic that overhead can be less, but a capability of error correction by the unit of ECC block is reduced. In addition, in the case of the lossless linking, which is to compensate for the lack of data in the linking loss area with the error correction capability, the error correction capability is reduced as in the 2 KB linking.
Patent document 1: Japanese Patent Application Laid Open NO. 2000-311346
Patent document 2: Japanese Patent Application Laid Open NO. 2001-23237